Azure IoT common library
Dependents: STM32F746_iothub_client_sample_mqtt f767zi_mqtt iothub_client_sample_amqp iothub_client_sample_http ... more
sastoken.c
- Committer:
- AzureIoTClient
- Date:
- 2017-03-24
- Revision:
- 23:ba126c6eb699
- Parent:
- 19:2e0811512ceb
- Child:
- 25:8507bf644fdf
File content as of revision 23:ba126c6eb699:
// Copyright (c) Microsoft. All rights reserved. // Licensed under the MIT license. See LICENSE file in the project root for full license information. #include <stdlib.h> #include "azure_c_shared_utility/gballoc.h" #include "azure_c_shared_utility/sastoken.h" #include "azure_c_shared_utility/urlencode.h" #include "azure_c_shared_utility/hmacsha256.h" #include "azure_c_shared_utility/base64.h" #include "azure_c_shared_utility/agenttime.h" #include "azure_c_shared_utility/strings.h" #include "azure_c_shared_utility/buffer_.h" #include "azure_c_shared_utility/xlogging.h" #include "azure_c_shared_utility/crt_abstractions.h" static double getExpiryValue(const char* expiryASCII) { double value = 0; size_t i = 0; for (i = 0; expiryASCII[i] != '\0'; i++) { if (expiryASCII[i] >= '0' && expiryASCII[i] <= '9') { value = value * 10 + (expiryASCII[i] - '0'); } else { value = 0; break; } } return value; } bool SASToken_Validate(STRING_HANDLE sasToken) { bool result; /*Codes_SRS_SASTOKEN_25_025: [**SASToken_Validate shall get the SASToken value by invoking STRING_c_str on the handle.**]***/ const char* sasTokenArray = STRING_c_str(sasToken); /***Codes_SRS_SASTOKEN_25_024: [**If handle is NULL then SASToken_Validate shall return false.**] ***/ /*Codes_SRS_SASTOKEN_25_026: [**If STRING_c_str on handle return NULL then SASToken_Validate shall return false.**]***/ if (sasToken == NULL || sasTokenArray == NULL) { result = false; } else { int seStart = -1, seStop = -1; int srStart = -1, srStop = -1; int sigStart = -1, sigStop = -1; int tokenLength = (int) STRING_length(sasToken); int i ; for (i = 0; i < tokenLength; i++) { if (sasTokenArray[i] == 's' && sasTokenArray[i + 1] == 'e' && sasTokenArray[i + 2] == '=') // Look for se= { seStart = i + 3; if (srStart > 0 && srStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') // look for either & or space srStop = i - 1; else if (sasTokenArray[i - 1] == '&') srStop = i - 2; else seStart = -1; // as the format is not either "&se=" or " se=" } else if (sigStart > 0 && sigStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') sigStop = i - 1; else if (sasTokenArray[i - 1] == '&') sigStop = i - 2; else seStart = -1; } continue; } if (sasTokenArray[i] == 's' && sasTokenArray[i + 1] == 'r' && sasTokenArray[i + 2] == '=') // Look for sr= { srStart = i + 3; if (seStart > 0 && seStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') seStop = i - 1; else if (sasTokenArray[i - 1] == '&') seStop = i - 2; else srStart = -1; } else if (sigStart > 0 && sigStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') sigStop = i - 1; else if (sasTokenArray[i - 1] == '&') sigStop = i - 2; else srStart = -1; } continue; } if (sasTokenArray[i] == 's' && sasTokenArray[i + 1] == 'i' && sasTokenArray[i + 2] == 'g' && sasTokenArray[i + 3] == '=') // Look for sig= { sigStart = i + 4; if (srStart > 0 && srStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') srStop = i - 1; else if (sasTokenArray[i - 1] == '&') srStop = i - 2; else sigStart = -1; } else if (seStart > 0 && seStop < 0) { if (sasTokenArray[i - 1] != '&' && sasTokenArray[i - 1] == ' ') seStop = i - 1; else if (sasTokenArray[i - 1] == '&') seStop = i - 2; else sigStart = -1; } continue; } } /*Codes_SRS_SASTOKEN_25_027: [**If SASTOKEN does not obey the SASToken format then SASToken_Validate shall return false.**]***/ /*Codes_SRS_SASTOKEN_25_028: [**SASToken_validate shall check for the presence of sr, se and sig from the token and return false if not found**]***/ if (seStart < 0 || srStart < 0 || sigStart < 0) { result = false; } else { if (seStop < 0) { seStop = tokenLength; } else if (srStop < 0) { srStop = tokenLength; } else if (sigStop < 0) { sigStop = tokenLength; } if ((seStop <= seStart) || (srStop <= srStart) || (sigStop <= sigStart)) { result = false; } else { char* expiryASCII = malloc(seStop - seStart + 1); /*Codes_SRS_SASTOKEN_25_031: [**If malloc fails during validation then SASToken_Validate shall return false.**]***/ if (expiryASCII == NULL) { result = false; } else { double expiry; for (i = seStart; i < seStop; i++) { expiryASCII[i - seStart] = sasTokenArray[i]; } expiryASCII[seStop - seStart] = '\0'; expiry = getExpiryValue(expiryASCII); /*Codes_SRS_SASTOKEN_25_029: [**SASToken_validate shall check for expiry time from token and if token has expired then would return false **]***/ if (expiry <= 0) { result = false; } else { double secSinceEpoch = get_difftime(get_time(NULL), (time_t)0); if (expiry < secSinceEpoch) { /*Codes_SRS_SASTOKEN_25_029: [**SASToken_validate shall check for expiry time from token and if token has expired then would return false **]***/ result = false; } else { /*Codes_SRS_SASTOKEN_25_030: [**SASToken_validate shall return true only if the format is obeyed and the token has not yet expired **]***/ result = true; } } free(expiryASCII); } } } } return result; } static STRING_HANDLE construct_sas_token(const char* key, const char* scope, const char* keyname, size_t expiry) { STRING_HANDLE result; char tokenExpirationTime[32] = { 0 }; BUFFER_HANDLE decodedKey; /*Codes_SRS_SASTOKEN_06_029: [The key parameter is decoded from base64.]*/ if ((decodedKey = Base64_Decoder(key)) == NULL) { /*Codes_SRS_SASTOKEN_06_030: [If there is an error in the decoding then SASToken_Create shall return NULL.]*/ LogError("Unable to decode the key for generating the SAS."); result = NULL; } else { /*Codes_SRS_SASTOKEN_06_026: [If the conversion to string form fails for any reason then SASToken_Create shall return NULL.]*/ if (size_tToString(tokenExpirationTime, sizeof(tokenExpirationTime), expiry) != 0) { LogError("For some reason converting seconds to a string failed. No SAS can be generated."); result = NULL; } else { STRING_HANDLE toBeHashed = NULL; BUFFER_HANDLE hash = NULL; if (((hash = BUFFER_new()) == NULL) || ((toBeHashed = STRING_new()) == NULL) || ((result = STRING_new()) == NULL)) { LogError("Unable to allocate memory to prepare SAS token."); result = NULL; } else { /*Codes_SRS_SASTOKEN_06_009: [The scope is the basis for creating a STRING_HANDLE.]*/ /*Codes_SRS_SASTOKEN_06_010: [A "\n" is appended to that string.]*/ /*Codes_SRS_SASTOKEN_06_011: [tokenExpirationTime is appended to that string.]*/ if ((STRING_concat(toBeHashed, scope) != 0) || (STRING_concat(toBeHashed, "\n") != 0) || (STRING_concat(toBeHashed, tokenExpirationTime) != 0)) { LogError("Unable to build the input to the HMAC to prepare SAS token."); STRING_delete(result); result = NULL; } else { STRING_HANDLE base64Signature = NULL; STRING_HANDLE urlEncodedSignature = NULL; size_t inLen = STRING_length(toBeHashed); const unsigned char* inBuf = (const unsigned char*)STRING_c_str(toBeHashed); size_t outLen = BUFFER_length(decodedKey); unsigned char* outBuf = BUFFER_u_char(decodedKey); /*Codes_SRS_SASTOKEN_06_013: [If an error is returned from the HMAC256 function then NULL is returned from SASToken_Create.]*/ /*Codes_SRS_SASTOKEN_06_012: [An HMAC256 hash is calculated using the decodedKey, over toBeHashed.]*/ /*Codes_SRS_SASTOKEN_06_014: [If there are any errors from the following operations then NULL shall be returned.]*/ /*Codes_SRS_SASTOKEN_06_015: [The hash is base 64 encoded.]*/ /*Codes_SRS_SASTOKEN_06_028: [base64Signature shall be url encoded.]*/ /*Codes_SRS_SASTOKEN_06_016: [The string "SharedAccessSignature sr=" is the first part of the result of SASToken_Create.]*/ /*Codes_SRS_SASTOKEN_06_017: [The scope parameter is appended to result.]*/ /*Codes_SRS_SASTOKEN_06_018: [The string "&sig=" is appended to result.]*/ /*Codes_SRS_SASTOKEN_06_019: [The string urlEncodedSignature shall be appended to result.]*/ /*Codes_SRS_SASTOKEN_06_020: [The string "&se=" shall be appended to result.]*/ /*Codes_SRS_SASTOKEN_06_021: [tokenExpirationTime is appended to result.]*/ /*Codes_SRS_SASTOKEN_06_022: [The string "&skn=" is appended to result.]*/ /*Codes_SRS_SASTOKEN_06_023: [The argument keyName is appended to result.]*/ if ((HMACSHA256_ComputeHash(outBuf, outLen, inBuf, inLen, hash) != HMACSHA256_OK) || ((base64Signature = Base64_Encode(hash)) == NULL) || ((urlEncodedSignature = URL_Encode(base64Signature)) == NULL) || (STRING_copy(result, "SharedAccessSignature sr=") != 0) || (STRING_concat(result, scope) != 0) || (STRING_concat(result, "&sig=") != 0) || (STRING_concat_with_STRING(result, urlEncodedSignature) != 0) || (STRING_concat(result, "&se=") != 0) || (STRING_concat(result, tokenExpirationTime) != 0) || (STRING_concat(result, "&skn=") != 0) || (STRING_concat(result, keyname) != 0)) { LogError("Unable to build the SAS token."); STRING_delete(result); result = NULL; } else { /* everything OK */ } STRING_delete(base64Signature); STRING_delete(urlEncodedSignature); } } STRING_delete(toBeHashed); BUFFER_delete(hash); } BUFFER_delete(decodedKey); } return result; } STRING_HANDLE SASToken_Create(STRING_HANDLE key, STRING_HANDLE scope, STRING_HANDLE keyName, size_t expiry) { STRING_HANDLE result; /*Codes_SRS_SASTOKEN_06_001: [If key is NULL then SASToken_Create shall return NULL.]*/ /*Codes_SRS_SASTOKEN_06_003: [If scope is NULL then SASToken_Create shall return NULL.]*/ /*Codes_SRS_SASTOKEN_06_007: [If keyName is NULL then SASToken_Create shall return NULL.]*/ if ((key == NULL) || (scope == NULL) || (keyName == NULL)) { LogError("Invalid Parameter to SASToken_Create. handle key: %p, handle scope: %p, handle keyName: %p", key, scope, keyName); result = NULL; } else { const char* string_key = STRING_c_str(key); const char* string_scope = STRING_c_str(scope); const char* string_name = STRING_c_str(keyName); result = construct_sas_token(string_key, string_scope, string_name, expiry); } return result; } STRING_HANDLE SASToken_CreateString(const char* key, const char* scope, const char* keyName, size_t expiry) { STRING_HANDLE result; /*Codes_SRS_SASTOKEN_06_001: [If key is NULL then SASToken_Create shall return NULL.]*/ /*Codes_SRS_SASTOKEN_06_003: [If scope is NULL then SASToken_Create shall return NULL.]*/ /*Codes_SRS_SASTOKEN_06_007: [If keyName is NULL then SASToken_Create shall return NULL.]*/ if ((key == NULL) || (scope == NULL) || (keyName == NULL)) { LogError("Invalid Parameter to SASToken_Create. handle key: %p, handle scope: %p, handle keyName: %p", key, scope, keyName); result = NULL; } else { result = construct_sas_token(key, scope, keyName, expiry); } return result; }